Another post about Les Paul circuitry customization: this time I’ll show the effect on the tone of substituting the volume potentiometer with a 250kOhm one (the standard being 500kOhm).
The graph shown is a logarithmic plot of the frequency response from 20Hz to 20kHz between the pickup ideal signal and the output, for the two choices of volume potentiometer, and for different positions of the volume knob (I set ten values of a logarithmic sweep from 1Ohm to 500kOhm).

As you can see the effect of the 250k volume pot is to smooth the resonant peak, making the sound a bit duller.
The effect becomes less and less significant the more you turn the tone knob towards the dark position, so here I show the results only for the brightest position.
(Btw, using a 250kOhm potentiometer for the tone knob would just be like keeping the stock 500kOhm one turned down a bit. Not interesting at all.)

Of course, this is a circuit simulation whit ideal components; if you want to know how this translates in reality just open your axe, check some different pots, and – as always – let your ears be the judge!

PS: The software I used for the simulation is Qucs on Linux, but on the website you can find downloads for Windows and Mac Os X as well.
There’s no potentiometer component in Qucs, so I just used two resistors with the values bond together by the equation Rvb=500k-Rva.
For the pickup I chose values that, looking at various sources, seem to be good representatives of a standard Gibson PAF pickup.